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Algae problem maybe

New pool owner here. We live in Mobile, Al. We have a 24,000 gal vinyl pool with a sand filter. Being a new pool guy I didnít know all the essentials to maintain a pool and the Chlorine level dropped and we had algae. Itís been a couple weeks and Leslie pool store said we have mustard algae, simply by a description of brushing it to a plume in the morning and color. It seems to be throughout the pool and on diagonals into the deep end. Mistakenly I shocked with powder chlorine and added tabs to inline chlorinator ( understand now thatís a no no ) and the CYA level is now up. Iíll post some pics and see it that helps. I want to say itís pollen since the FC level has been over 10ppm for weeks and it hasnít improved, but then again maybe I didnít shock it to a high enough FC level.
Should I pump it down, maybe during a vacuum to waste to clean the bottom and lower the CYA.
Any help is greatly appreciated
What do ya think?Attachment 43212Attachment 43213Attachment 43214

Re: Algae problem maybe

Hello! If we were to assume the pool store test were close (which we usually don't rely upon), your CYA is one major issue. It's extremely hard to keep the pool properly sanitized when the CYA is over 100. First and foremost though, before you try to remedy the situation, I highly encourage your to get your own test kit. I recommend the TF-100 (link below) as it uses Taylor reagents but in larger capacities which is a better value. Until you can test the water on your own with accurate results, you may be adding chemical not warranted. Until you can get your own test kit, simply add one gallon of regular liquid bleach to your water each day. When you get the test kit, post a full set of numbers and we can advise you from there. We look forward to hearing from you again. Let us know if you have any more questions.

Re: Algae problem maybe

Welcome to TFP!

You could have well over 100 Cya, but it's hard to know without your own testing. Often, it's higher than pool store testing but it's a guess. I would suggest getting your own kit to be sure, and begin a study of pool school. Re-read the ABCs, and ask all the questions you need to. Adding pucks or shock isn't bad on its own, but adding things without your own kit to test, then determine the need for, and results of additions will get you in trouble. No problem though, with a little knowledge and good test results you can like this out quite easily.

Re: Algae problem maybe

Right now, the gallon per day is simply to keep things from getting too much worse. It won't remove all the algae. The pics looks like regular algae so far. Regardless though, the treatment for MA is the same as regular algae, with one exception at the end which we can address later when you get your kit. When you get your kit, you'll need to "SLAM" via the link below in my sig. So you should get familiar with that in advance.

Also, please add your pool info to your signature by going to the top of the TFP web page (just under the Pool School button) and select "SETTINGS". On the next page look to the left for a menu bar that says, “MY SETTINGS” and go to "EDIT SIGNATURE" to enter your pool and equipment info there. It will help us later.

One more suggestion - consider requesting the "speed stir". It makes mixing so much easier.

We suspect your CYA could be higher then 100, and it is recommended that you perform a "dilution CYA test". Mix 50% tap water and 50% pool water (shake well) and use this for your testing. Then multiply by 2. If your CYA test is 80, then your true CYA is 160. This should be your first test as the SLAM level to clear up your pool all is based on your CYA. Depending on your CYA level, we may recommend that you replace some water before starting the SLAM process. Please keep us posted!

Re: Algae problem maybe

Catanzaro,

Thanks for the advice. Speed stir is on its way as well.

Looking through the Pool School info, I didn't see any numbers for draining and refilling based on high CYA levels. If my test reveals high CYA levels anyone have an idea of how much water needs to be replaced?

Re: Algae problem maybe

OUCH! Any advice for this with for a vinyl pool?

.. For starters, no more pool store testing.

.. You will need to replace a minimum 50% of your water. This should bring your CYA low enough to actually start the SLAM process, and while SLAM is occurring, then you can replace the additional water needed to your comfortable level. If you are planning on closing the pool, a level of 60-70 could be acceptable as you could always lower your level in the spring and the CYA may drop during the winter months. For some reason, I always seem to loose 20 ppm during the winter.

.. Your TA is also probably high, but your PH is low. Usually a high TA has a higher PH. Did you wipe the dropper bottle while performing the TA test? This could lead a high false reading. The 3" tablets could have contributed to the lower PH as well.

Next year, you may find that your PH will have a tendency to drift upwards pretty quickly based on higher TA, so please keep an eye on PH and test daily, if needed. And as Tim mentions (Drain/Fill) and repeat process so the liner does not develop wrinkles, shifts or floats.

Re: Algae problem maybe

I have been using baking soda to raise PH. At the time I didn’t realize Borax was an option to raise PH without raising Alkilinity?

Guess I’ll start draining. I’ll take the CYA to the 60-70 and see what happens over the winter. We do plan to close the pool. Would you recommend filling to the normal level for the SLAM process then drain?

Re: Algae problem maybe

I drained it down to 2 feet in shallow end and refilled. Added a gallon of bleach tonight.
At what point should I retest CYA?
Is it important to maintain FC Levels relative to CYA during the drain & refill stage?
Definitely need to slam after this, pool is getting green.